A Low-Energy Lighting Strategy for High-Yield Strawberry Cultivation Under Controlled Environments

Optimizing light conditions in controlled-environment agriculture is critical for enhancing crop yield and energy efficiency, particularly in high-value crops like strawberries, where precise spectral tuning can significantly influence both vegetative growth and fruit production. In this study, a windmill-style vertical farming system was developed to facilitate efficient strawberry cultivation under low-light conditions. A custom LED lighting fixture, measuring 3 m in length, was suspended 30 cm above the canopy to uniformly illuminate a planting zone of 3.0 m × 0.3 m. The lighting system, which combines red (655–665 nm) and full-spectrum white LEDs, was optimized using a particle swarm optimization (PSO) algorithm to enhance spatial light distribution. The uniformity of photosynthetic photon flux density (PPFD) improved from 71% to 85%, and the standard deviation decreased from 75 to 15. Under a 16 h optimized lighting regime, strawberry plants exhibited a 55% increase in height compared to the non-supplemented control group (Group D), a 40% increase in leaf width, and a 36% increase in fruit weight (69.76 g per plant) relative to the 12 h supplemental lighting group (Group A). The system operates at a fixture-level power consumption of just 160 W, with its spectral output aligned with the absorption characteristics of strawberry foliage and fruit. These results demonstrate that an algorithm-driven lighting layout can significantly enhance both vegetative and reproductive performance in vertical strawberry farming while maintaining high energy efficiency.